> Said another way, you should never think of animations discretely (i.e. "slide in from left") if you're thinking about building touch-based app. It won't feel natural.
That kind of goes against thinking of animation as tweens. Instead, you want something more physics based that can respond to touch in real time yet remain controllable enough for user interface usage; e.g. verlet and/or inverse kinematics.
react-tween-state is less about the specific tweening function and more about the idea of a numeric value changing over time that can be interrupted. Instead of the standard Penner tweening functions you could just as easily substitute in some physics (like https://github.com/facebook/rebound-js). And with the DESTRUCTIVE mode of react-tween-state you can seamlessly transition between direct manipulation mode and inertia mode.
There's still a lot to do here, but I am pretty positive on the overall approach.
Reading the github page, though, this is really about tweening with no mention of interruption. However, using Verlet (not Newtonian like rebound-js!) you can easily combine both approaches since Verlet allows you to mess with a position directly (velocity is implicit in position deltas, so really stable although less accurate).
I wrote a rejected paper about this a few years ago; it might be useful as a reference:
I wrote that when I was doing a lot of work with WPF, whose animation/data binding system is fairly similar to what is being explored in Javascript today (with frameworks like React). But beyond data binding and canned animations, I think physics is the next step.
> stackBehavior (default: tweenState.stackBehavior.ADDITIVE). Subsequent tweening to the same state value will be stacked (added together). This gives a smooth tweening effect that is iOS 8's new default... The other option is tweenState.stackBehavior.DESTRUCTIVE, which replaces all current animations of that state value by this new one.
This is not much different from WPF's animation support, and I don't think it really helps. The interruptions are still not very natural looking. It was definitely useless for Surface (the table, not the tablet) when I was doing UX prototypes for it.
That kind of goes against thinking of animation as tweens. Instead, you want something more physics based that can respond to touch in real time yet remain controllable enough for user interface usage; e.g. verlet and/or inverse kinematics.